X is for Xylitol Toxicity
A number of years ago, I received a telephone call while on-call. The person informed me that her dog ate a piece of chocolate cake. I asked some more specific questions: What size is your dog? How much chocolate cake did it get? Was it a cake made from a box or from a gourmet bakery? Etc. Based upon her answers, I informed the woman that the likelihood of her dog having any problems was minimal (pretty much zero) as it only took a small bite and it was a box mix which does not have much chocolate in it. The woman than said, “I don’t know if you know this, but chocolate is toxic to dogs.” I thanked her for the information, and yes, I was aware, but the toxicity is based on type of chocolate (milk chocolate is not as bad as dark chocolate which is not as bad as baker’s chocolate), size of the dog, and the amount of chocolate eaten (a bigger dog can eat more than a small dog with less complications). I told her what to watch for in case there were any problems and asked her to call again if she noticed any. There have been other times in my career that I have had a very different conversation when it comes to toxicity. In 2004, the conversations about toxicity started to grow as a new toxin emerged on the veterinary scene: Xylitol.
Xylitol is a chemical compound that is made most commonly from birch trees and is used as a sugar substitute. It is most commonly found in sugar-free gum, candies, and in many forms of toothpaste. Some people, especially diabetics, use it as a sugar substitute in cooking. Due to the slow absorption in people, there are very few side effects, although some people complain of diarrhea after ingestion of even small amounts. When reading labels you may also see xylitol listed as Eutrit, Kannit, Newtol, Xylite, Torch, or Xyliton.
In dogs there is a very fast absorption rate, often within 30 minutes, and signs and symptoms of xylitol poisoning can develop rapidly. That being said, since toxicity normally develops from eating the gum which is meant to be chewed, it can take up to 12 hours for symptoms to develop since dogs rarely chew and just swallow the gum. The most commonly seen sign is severe hypoglycemia (low blood sugar) that comes as a result of rapid release of insulin from the pancreas into the blood stream. If the dog’s blood sugar drops low enough, coma and death can occur rapidly as well. Other side effects include liver disease with secondary bleeding, liver failure, and death. Cows, goats, and rabbits also show a significant release of insulin in response to xylitol. At this time, it is unknown how cats respond to xylitol.
How much xylitol does it take to make a dog sick?
We know that as little as 100 mg/kg (45 mg/lb) requires decontamination and monitoring, with dogs receiving more than this requiring supportive care. In the case of baking xylitol (the granulated form), 1 cup weights 190 grams. When it comes to gum and candy, the difficult part is that manufacturers do not always list how much xylitol is in their products. Estimates range from 0.9-1,000 mg per piece of xylitol containing gum. Clinically, we can see toxicity in a 20 pound (9 kg) dog with as little as 1 small piece of gum. Therefore, it is essential to contact your veterinarian (or veterinary emergency clinic) immediately upon knowledge or suspicion of ingestion of sugar-free products. If possible, have the packaging available when you speak with the veterinarian or bring it with you if going straight to a veterinary clinic or hospital. In the United States, you can contact the Pet Poison Hotline at 800-213-6680 or the ASPCA Poison Hotline at (888) 426-4435, although there is a fee associated with the call it may save you some money when going to the veterinarian.
What should I expect when I get to the veterinary clinic?
You should expect to have a history and complete examination performed. If your dog is not showing symptoms and the ingestion was recent, he or she may be given medication to induce vomiting which will hopefully remove the ingested substance from the stomach and then do appropriate diagnostics and supportive care. If your dog is already showing signs of toxicity, the veterinary team may obtain blood and urine samples and place an IV catheter. Blood tests should include chemistry, electrolytes, and complete blood count (CBC). They may also check clotting times (PT and aPTT) and fibrinogen levels, especially if there are already signs of bleeding. Once low blood sugar has been documented, then IV fluids containing dextrose will be started. Your dog may need to remain on IV fluids for 24-72 hours or until the blood glucose has stabilized. Multiple checks of glucose will be performed (usually only needing a few drops of blood) and liver values will also be monitored to make sure there is no worsening or liver disease.
If caught early in the process or if it is a mild case, the prognosis is generally very good. Waiting to seek medical attention until after symptoms start or in ingestion of large amounts of xylitol, prognosis worsens significantly.
Ways to prevent xylitol toxicity include not having xylitol containing products in the home or keeping them far out of reach of animals (which can be difficult if there are children in the home) and knowing what is in the products you have. Double check all products labeled as sugar-free.
Remember that although this can be fatal, it is usually treatable. What should you do if you suspect or know that your pet has been poisoned? Click HERE.